Hermetic electrical connectors are important to a significant number of industries, in a significant number of applications. An example includes use with the electronic safe and arming device industry, where exploding foil initiator technology slapper detonators are used to initiate warheads or distribute payloads in missiles, guided projectiles, and submunitions. Other examples of such use are in oil recovery, mining, and demolition devices.
The need for hermetic connections arises from the effects of moisture and water condensation in electronic packages. Salts and ionic contaminants dissolved within the moisture serve to degrade the reliability of electrical components inducing both ohmic changes in electrical connections as well as chemical changes in semiconductor materials. To prevent the undesirable degradation of performance which often results, low leakage hermetic connections are needed to preclude or minimize moisture intrusion and the associated chemical activity.
Typical hermetic connectors presently used include glass to metal seals or ceramic/metal feed-throughs. These connectors suffer from a number of disadvantages. Such connectors are expensive due to the thermal processing required to fire and cure the glass and ceramic materials. They are also sensitive to mechanical shock because of the brittle nature of the glass and ceramic materials. Since brittle materials are inherently weak in flexure, they are typically designed to take advantage of the stronger shear properties of glass. The resulting configurations are inherently thick, which causes large inductive losses for high current applications.
Harnesses involving multiple conductors and flat cable feed-throughs also exhibit leakage at the edges, where imperfect blending of the cable laminations occurs in areas of non-uniform thickness. Unwanted leakage paths are induced within the cable-referred to as "soda straw" leakage--making the connection susceptible to moisture intrusion where it passes through a bulkhead from outside of an electronic package to inside.
Therefore, what is needed is a flexible, inexpensive, low profile hermetic electrical connection to provide means to maintain a low moisture volume within an electrical package to assure high reliability and long service life.